Driver IC, a print head having the driver IC and a printer including the print head

Abstract

A driver IC includes a plurality of electrode pads on a belt-shaped power supply electrode. The electrode pads are arrayed with a pitch dividing a row of driver circuits into groups of equal number. A power source voltage VDD is supplied through the plurality of the electrode pads. Further, the power supply electrode is disposed between the digital circuits and the driver circuits. A print head includes the driver IC with a plurality of light emitting elements connected thereto. A printer includes the print head in combination with photo sensitive drum, a lens array, a charger, a developer and a transcriber.

What is claimed is: 
     
       1. A driver integrated circuit, comprising: (a) a substrate;   (b) a plurality of input electrodes arranged on the substrate for receiving input signals;   (c) a plurality of output electrodes arranged on the substrate for outputting driving signals therefrom to drive loads;   (d) a plurality of digital circuits arranged on the substrate between the input electrodes and the output electrodes, each of the digital circuits receiving the input signals from respective ones of the input electrodes, and producing a logic signal based on the input signals;   (e) a plurality of driver circuits arranged on the substrate between the digital circuits and the output electrodes for driving logic signals delivered from the digital circuits and outputting driving signals to the output electrodes, an input of each of the driver circuits being connected to a respective one of the digital circuits and an output of each of the driver circuits being connected to a respective one of the output electrodes; and   (f) a power supply electrode on the substrate,   wherein the power supply electrode is a belt-shaped electrode which is arranged between the digital circuits and the driver circuits, the power supply electrode being arranged in parallel with the digital circuits and the driver circuits, the belt-shaped electrode including at least three electrode pads, spaced apart by distances that are approximately equal, to receive power from an external power source, the power supply electrode pads being disposed at a pitch derived by equally dividing the plurality of driver circuits into groups and the power supply electrode being connected to another input of each of the driver circuits for supplying power to the driver circuits.   
     
     
       2. A driver integrated circuit as set forth in claim 1, wherein each of the digital circuits is connected to one of the driver circuits by a single straight conductive line. 
     
     
       3. A driver integrated circuit as set forth in claim 1, wherein the driver circuits have a width and the digital circuits have a width which is equal to that of the driver circuits. 
     
     
       4. A driver integrated circuit as set forth in claim 1, wherein each of the digital circuits comprises a shift register stage, a latch circuit and an AND circuit. 
     
     
       5. A driver integrated circuit as set forth in claim 1, wherein each of the digital circuits comprises a shift register stage, a latch circuit and a transfer gate. 
     
     
       6. A driver integrated circuit as set forth in claim 1, wherein the driver circuits comprise MOS transistors. 
     
     
       7. A driver integrated circuit is set forth in claim 1, wherein the driver circuits comprise bipolar transistors. 
     
     
       8. A print head, comprising: (i) a plurality of driver integrated circuits, each including (a) a substrate;   (b) a plurality of input electrodes which are arranged on the substrate for receiving a print data signal and a strobe signal;   (c) a plurality of output electrodes which are arranged on the substrate for outputting driving signals therefrom to drive loads;   (d) a plurality of digital circuits which are arranged on the substrate between the input electrodes and the output electrodes and which are responsive to the print data signal and the strobe signal, each of the digital circuits receiving the print data signal and the strobe signal from respective input electrodes, and producing a logic signal based on the print data signal and the strobe signal;   (e) a plurality of driver circuits which are arranged on the substrate between the digital circuits and the output electrodes for driving logic signals delivered from the digital circuits and outputting driving signals to the output electrodes, an input of each of the driver circuits being connected to a respective one of the digital circuits and an output of each of the driver circuits being connected to a respective one of the output electrodes; and   (f) a belt-shaped power supply electrode which is arranged on the substrate between the digital circuits and the driver circuits, the power supply electrode being arranged in parallel with the digital circuits and the driver circuits, the belt-shaped power supply electrode including at least three electrode pads, spaced apart by distances that are approximately equal, to receive power from an external power source, the power supply electrode pads being disposed at a pitch derived by equally dividing the plurality of driver circuits into groups, the power supply electrode being connected to another input of each of the driver circuits for supplying power to the driver circuits, and     (ii) a plurality of light emitting elements, each one of the plurality of light emitting elements being connected to a respective one of the output electrodes of the driver integrated circuit and each one of the plurality of light emitting elements being driven by a respective driver integrated circuit.   
     
     
       9. A print head as set forth in claim 8, wherein each of the the digital circuits is connected to one of the driver circuits by a single straight conductive line. 
     
     
       10. A print head as set forth in claim 8, wherein the driver circuits have a width and the digital circuits have a width which is equal to that of the driver circuits. 
     
     
       11. A print head as set forth in claim 8, wherein the light emitting elements comprise light emitting diodes. 
     
     
       12. A printer, comprising: (i) a print head for emitting light, the print head being driven by driving signals based on video signals having print data for each picture element;   (ii) a converging means for focusing light emitted from the print head;   (iii) a photo-sensitive drum means responsive to exposure to the light focused by the converging means for forming an electrostatic latent image thereon;   (iv) an electro-charging means for electrically charging the photo-sensitive drum;   (v) a developing means, for using toner to develop an electrostatic latent image area formed on a surface of the photo-sensitive drum; and   (vi) a transcribing means for transcribing the toner onto a recording medium;   wherein the print head comprises a plurality of driver integrated circuits, each including (a) a substrate,   (b) a plurality of input electrodes which are arranged on the substrate for receiving a print data signal and a strobe signal,   (c) a plurality of output electrodes which are arranged on the substrate for outputting driving signals therefrom to drive loads,   (d) a plurality of digital circuits which are arranged on the substrate between the input electrodes and the output electrodes and which are responsive to the print data signal and the strobe signal, each of the digital circuits receiving the print data signal and the strobe signal from respective input electrodes, and producing a logic signal based on the print data signal and the strobe signal,   (e) a plurality of driver circuits which are arranged on the substrate between the digital circuits and the output electrodes for driving logic signals delivered from the digital circuits and outputting driving signals to the output electrodes, an input of each of the driver circuits being connected to a respective one of the digital circuits and an output of each of the driver circuits being connected to a respective one of the output electrodes, and   (f) a belt-shaped power supply electrode which is arranged on the substrate between the digital circuits and the driver circuits, the power supply electrode being parallel with the digital circuits and the driver circuits, the power supply electrode including at least three electrode pads, spaced apart by distances that are approximately equal, to receive power from an external power source, the power supply electrode pads being disposed at a pitch derived by equally dividing the plurality of driver circuits into groups, and the power supply electrode being connected to another input of the driver circuits for supplying power to the driver circuits, and     wherein the print head further comprises a light emitting means having a plurality of light emitting elements, each one of the plurality of light emitting elements being connected to a respective one of the output electrodes of the driver integrated circuit and each one of the plurality of light emitting elements being driven by a respective driver integrated circuit.   
     
     
       13. A printer as set forth in claim 12, wherein each of the digital circuits is connected to one of the driver circuits by a single straight conductive line. 
     
     
       14. A printer as set forth in claim 12, wherein the driver circuits have a width and the digital circuits have a width which is equal to that of the driver circuits. 
     
     
       15. A printer as set forth in claim 12, wherein the converging means comprises a convergent rod lens array. 
     
     
       16. An integrated circuit, comprising: a substrate;   a plurality of drive circuits arranged on the substrate in a row;   a plurality of digital circuits arranged on the substrate in a row which is substantially parallel to the row of driver circuits;   a plurality of wiring conductors, the wiring conductors connecting each of the digital circuits to an input of each of the driver circuits; and   an elongated power supply electrode which is arranged on the substrate between the row of digital circuits and the row of driver circuits, to distribute power from an external power source to the driver circuits, the power supply electrode being connected to another input of each of the driver circuits, the power supply electrode being substantially parallel to the row of driver circuits, the power supply electrode including at least three electrode pads, spaced apart by distances that are approximately equal, to connect to the external power source.   
     
     
       17. An integrated circuit as set forth in claim 16, wherein the power supply electrode has a width that is substantially uniform. 
     
     
       18. An integrated circuit as set forth in claim 16, wherein the digital circuits include AND circuits.